#include <fstream>
#define cin fin
#define cout fout
using namespace std;

ifstream fin("flip.in");
ofstream fout("flip.out");

int main()
{
    int a[17][17], n, m;

    int sln[17] = {0};
    int slm[17] = {0};

    int scn[17] = {0};
    int scm[17] = {0};

    cin >> n >> m;
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
        {
            cin >> a[i][j];

            sln[i] += a[i][j];
            slm[i] += (-a[i][j]);

            scn[j] += a[i][j];
            scm[j] += (-a[i][j]);
        }

    for (int i = 1; i <= n; ++i)
    {
        if (sln[i] < slm[i])
        {
            for (int j = 1; j <= m; ++j)
                a[i][j] = -a[i][j];
        }
    }

    for (int j = 1; j <= m; ++j)
    {
        if (scn[j] < scm[j])
        {
            for (int i = 1; i <= n; ++i)
                a[i][j] = -a[i][j];
        }
    }

    int s = 0;
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
            s += a[i][j];

    cout << s;
}